text/koot_nightwatch/2 matches the site

public static LinguisticObject Authorship_And_Publication()
{
    var koot = new LinguisticObject()
        .WithContext()
        .WithId("https://linked.art/example/text/koot_nightwatch/2")
        .WithLabel("Content of Koot's Night Watch")
        .WithClassifiedAs(Aat.Monograph, Aat.TypeOfWork);

    koot.CreatedBy = new Creation()
    {
        Label = "Koot's writing of the work",
        CarriedOutBy = [
            new Person()
                .WithId("https://linked.art/example/person/koot")
                .WithLabel("Ton Koot")
        ]
    };

    koot.UsedFor = [
        new Activity()
        {
            Label = "MI's Publishing",
            ClassifiedAs = [ Aat.PublicationActivity ],
            TimeSpan = LinkedArtTimeSpan.FromYear(1969),
            CarriedOutBy = [ 
                new Group()
                    .WithId("https://linked.art/example/group/meulenhoff")
                    .WithLabel("Meulenhoff International")
            ]
        }
    ];

    return koot;
}

• Metatype classification The second argument classifies the first, not the object: WithClassifiedAs(Aat.Description, Aat.Statement) says this is a Description, and Description is a kind of Statement. The Plain C# form shows the nesting.

var linguisticObject = new LinguisticObject
{
    Context = ["https://linked.art/ns/v1/linked-art.json"],
    Id = "https://linked.art/example/text/koot_nightwatch/2",
    Label = "Content of Koot's Night Watch",
    ClassifiedAs =
    [
        new Type("http://vocab.getty.edu/aat/300060417", "Monograph")
        {
            ClassifiedAs = [Aat.TypeOfWork],
        },
    ],
    CreatedBy = new Creation
    {
        Label = "Koot's writing of the work",
        CarriedOutBy =
        [
            new Person
            {
                Id = "https://linked.art/example/person/koot",
                Label = "Ton Koot",
            },
        ],
    },
    UsedFor =
    [
        new Activity
        {
            Label = "MI's Publishing",
            ClassifiedAs = [Aat.PublicationActivity],
            CarriedOutBy =
            [
                new Group
                {
                    Id = "https://linked.art/example/group/meulenhoff",
                    Label = "Meulenhoff International",
                },
            ],
            TimeSpan = new LinkedArtTimeSpan
            {
                BeginOfTheBegin = new LinkedArtDate(1969, 1, 1),
                EndOfTheEnd = new LinkedArtDate(1969, 12, 31, 23, 59, 59),
            },
        },
    ],
};

Generated from the object the example builds: every property that is set, as object initialisers, with the vocabulary constants where a term is in the registry. The fluent helpers are a convenience, not a requirement; this form and the one as written produce the same JSON.